NATO’s having a presence in a member state is protection. It reduces the chance of opportunists like Putin invading.
Putin tried to call NATO’s bluff, using Ukraine as a bargaining chip. NATO didn’t blink, and so he started a war. He doesn’t get to do the abuser thing of saying “see what you made me do”. This is on him, and him alone.
He can demand that NATO withdraw all he likes, and I’d have some sympathy for that if it didn’t involve invading another country as leverage. Note, I say some sympathy, not that NATO should actually do it, especially as Putin’s regieme has threatened other countries already.
It depends what you want to do with it. If it’s just for storing files/backups then encrypt them before uploading and make sure the key never goes anywhere near the VPS. If it’s for serving up something like a simple website, you probably care more about data integrity than exfiltration, so make sure you have the security, including selinux or equivalent, locked down, and regularly run integrity checks. If it’s for running something interactive, or where data will be generated or downloaded to the machine, you’re out of luck, there’s no even theoretical way of securing that against an adversary with that much access.